Device for production of copy by diffusion transfer



June 6, 196? H. KLEBNSTRA 3,323,435

DEVICE FOR PRODUCTION OF COPY BY DIFFUSION TRANSFER Filed NOV. 2, 1964 INVENTOE Harm A Zemsim United States Patent O i 3,323,435 DEVICE FOR PRODUCTION OF COPY BY DIFFUSION TRANSFER Harm Kleinstra, Utrecht, Netherlands, assignor to A. B.

Dick Holland N.V., Utrecht, Netherlands, a corporation of the Netherlands Filed Nov. 2, 1964, Ser. No. 408,082 Claims priority, application Germany, Nov. 2, 1963, A 44,457

4 Claims. (Cl. 95-89) This invention relates to the production of copy by diffusion transfer from anjexposed silver halide negative onto a coated copy sheet onto which the exposed silver halide is transferred by diffusion for reduction to reproduce the image and it relates more particularly to the developing apparatus through which the exposed negative and copy sheets are advanced for wetting at least one of the paperswith a developing liquid for diffusion transfer and image development.

In the previously issued Patent No. 2,846,933, illustration is made of a device for effecting the diffusion transfer process with carriers coated with the light-sensitive and photographic layers. The device includes vertically spaced apart guide members or plates for introduction of the separated coated carriers which are guided through the path of the developing liquid and which includes means such as squeeze rollers arranged above the liquid level and in the path of the carriers emerging from the bath for pressing the carriers together to permit transfer by diffusion and to squeeze out excess liquid. In the previously issued Patent No. 2,865,275, description is made of a similar device in which use is made of a pendulum or swing adapted to be engaged by the leading edges of the carriers for guiding the coated carriers from the ends of the spaced guides to the squeeze rolls. In the embodiments described in the aforementioned patents, both of the coated carriers, that is the exposed negative and the coated positive sheet, are guided through the bath for wetting with the developing liquid. Presently, coated carriers are available commercially in which only the coated carrier corresponding to the liquid silver halide negative need be wet with the developing liquid while the other coated carrier or positive sheet can be allowed to remain dry thereby to produce dryer copy and to provide greater rigidity and strength to the carrier during processing through the machine.

Thus it is an object of this invention to produce a device of the type described in which the coated carriers can be advanced therethrough in a manner to wet only the exposed negative with the developing liquid but which is also capable of adjustment to wet both the positive and negative sheets, if desired. a Another object is to produce a developing device of the type described in which the squeeze rollers are mounted for adjustment to increase the squeezing action while the device is in use and to relax the rollers when not in use, and it is a related object to produce a simple and compact device of the type described for use in the production of copy by diffusion transfer techniques in which the developing liquid can be introduced into the device for use and removed when the device is not in use; in which the developing liquid can be maintained at a predetermined level in the device for wetting only one of the carriers while the other remains dry until brought in contact with the wetted carrier for diffusion transfer; in which a greater squeezing action can be effected for more intimate contact between the carriers and whereby larger amounts of developing liquid can be recovered from the carriers to conserve upon the amount of liquid that is removed from the system and to produce better and dryer copy.

These and other objects and advantages of this invention ice will hereinafter appear and for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawing, in Which FIG. 1 is a sectional elevational view of a device embodying the features of this invention, and

FIG. 2 is a top plan view of the back portion of the device shown in FIG. 1.

In accordance with the practice of this invention, the limitation of the developing liquid to a level sufficient to wet only one of the carriers will operate beneficially to require less of the developing liquid in the development tank of the device but, in order to maintain the level of the liquid to avoid wetting of the other carrier, means are required accurately to control the liquid level in the tank.

In accordance with the concepts of the invention, means are provided for an air tight storage container for the developing liquid and means are supplied for connecting the container with the tank whereby liquid will be introduced into the tank to fill the tank to a predetermined level and to maintain the liquid at that level during use of the device and to drain the liquid from the tank for return to the container during non-use of the device, and for effecting displacement of the squeeze rollers into more substantial contact one with the other responsive to the adjustment of the container for introducing liquid into the tank for conditioning the device for use in the production of copy.

The device represented by the drawing comprises a tank 1 for the developing bath. At the supply side of the tank, a pair of guide members or plates 2 and 3 are provided for introducing the coated carriers. The guide member 3 is dimensioned to have a length greater than the guide member 2 whereby the inner end portion extends beyond the innermost end of the guide member 2 in the manner of a paddle with a smooth upwardly curved end portion. One coated carrier corresponding to the positive sheet is introduced between the guide members 2 and 3 and the other coated carrier corresponding to the exposed negative is introduced between the guide member 3 and the bottom wall of the tank 1.

Pendulum arms 7 are suspended for rocking movement from a pivot 8 on the inner walls of the tank 1. Extending crosswise between the lower ends of the pendulum arms is a transfer strip 6 having spaced parallel tongues 5 extending forwardly therefrom with an end portion 4 of the tongues being turned upwardly as a lip or flange. Fixed to' the bottom wall of the tank below a pair of squeeze rollers 10 and 11 is a stripper member 9 having laterally spaced apart nose-shaped projections which extend upwardly towards the nip of the rollers and in the path of the tongues extending forwardly from the transfer strip with the nose-shaped projections being spaced one from another to correspond with the spaced relationship between the tongues and with the width of the nose-shaped projections being less than the width of the space between the tongues and with the nose-shaped members being spaced one from the other by an amount greater than the width of the tongues so that the tongues will pass forwardly between the nose pieces when the transfer strip 6 is rocked forwardly towards the rollers.

The rollers 10 and 11, formed of a resilient material, are provided with shafts, the ends of which are received in slots in the side walls of the tank to mount the rollers for rotational movement. At least one of the rollers, preferably roller 10, is a driven roller which is adapted to be rotated by an electrical motor (not shown).

In FIG. 1, illustration is made of the device in operative condition with the developing liquid maintained in the tank at the desired level for contacting the lower side of the guide member 3 so as to cause immersion of the coated carrier advanced between the guide member 3 and the bottom of the tank.

When the coated carrier to be kept dry, and onto which the positive image is to be transferred, is introduced between the guide members 2 and 3 at the same time as the exposed coated carrier to be guided through the developing liquid, and on which the latent negative image has been developed is introduced between the guide member 3 and the bottom 1 of the developing tank, the leading edge of the latter will engage the lips 4 of the tongues 5. In response to continued forward displacement of the coated carrier, the transfer strip is rocked forwardly about the pendulum pivots to guide the coated carrier forwardly towards the nip of the squeeze rolls. As the tongues 5 pass between the nose pieces 9 of the stripper member, the leading edge of the coated carrier is lifted from the lips 4 for feeding into the nip between the squeeze rollers. When the coated carrier has been lifted from the lips by the tongues 5, the pendulum-like supporting and guiding member falls back to its starting position.

The coated carrier introduced between the guide members 2 and 3 does not come into contact with the developing liquid within the device and is guided upwardly by the curvilinear end portion of the guide member 3 in a manner such that the leading edge comes into contact with the other coated carrier while it is being guided by the supporting and guiding members 4-7 respectively whereupon both carriers are led together into the nip of the squeeze rollers 10 and 11. In this way, the moistened coated carrier is brought into intimate contacting relationship with the still dry coated carrier and excess de veloping liquid is squeezed out.

A cylindrically-shaped container 12 is provided for the developing liquid. The container is in turn mounted on a drum 20 for the feed of liquid from the container into the drum. The drum is mounted on a horizontal shaft for enabling reciprocal movement and it is provided with a closure member 20. As shown in FIG. 2, two short nose pieces 13 and 14 extend from openings in the closure 20 to connectors in the side wall of the developing tank 1 through short passages 15 and 16. Said short passages 15 and 16 discharge into a small gutter 18 interconnecting the apertures and forming an outwardly displaced portion in the tank side wall. The upper part of the gutter is closed by a disc 17 received Within a slotted portion for vertical displacement for adjusting the level of liquid in the tank. The outside diameter of the disc 17 controls the level of the liquid developing bath ac cording to the principles of the Mariotte bottle and can be adjusted to maintain the level of liquid in the tank to a predetermined height. The aperture and the pipe 16 are located in the lowermost portion of the bottom of the tank 1.

When the storage tank with the drum and shaft is rotated into the raised position, shown in FIG. 2, the liquid flows from the container and drum into the developing tank by an amount to fill the tank to the level determined by the lowermost edge of the disc 17. Liquid continues to be supplied from the container to maintain that level in response to use of the liquid from the bath. When the container 12 and its associated parts is rotated to the lowered position, about 180, the liquid drains from the bath and is substantially completely emptied into the container 12 through the aperture of the pipe or passage 16.

In the event that the disc 17 is removed and the guide plate 3 is replaced by a shorter guide member corresponding in length to the guide member 2, this same device can be adapted for use in the diffusion transfer technique wherein the coated carrier on which the latent negative image is present as well as the coated carrier onto which the image is to be transmitted are both guided through the developing liquid. The level of the liquid in the developing bath will rise to the level of the upper edge of the hole and the pipe or passage 15.

In FIG. 2, illustration is made of the mechanism whereby the squeezing pressure on one of the squeezing rollers 11 can be increased in response to rotation of the container to filling position and vice versa.

A shaft 22, having a bearing in the wall of the tank 1, is mounted on the tank for rotational movement. A lever arm 21 is fixed as a torque arm on one end of the shaft and is provided with a saddle-shaped end portion terminating in a forked member 26 adapted to receive pin 19 extending laterally from the closure 20 in a position offset from its center whereby rocking movement of the container is imparted to the arm 21 for rotation of the shaft 22 in response to rotational movement of the drum 20. A lever arm 23 is connected onto another portion of the shaft 22 for rocking. movement with the shaft during rotational movement thereof.

A linking bar 24 is pivoted at one end onto the end portion of the arm 23 while the other end is pivotally connected to a shoe 28 which surrounds an end portion of the shaft 30 of the squeeze roll 11 in a portion of the shaft extending outwardly beyond the wall of the tank 1. A compression spring 29 is concentrically mounted about the linking bar 24 with one end bearing against a stop disc 29 while the other end bears against a ring 29 slidably mounted on the link to bear against the saddle 28 and indirectly onto the shaft 30.

The lever arms 21 and 23 are attached to the shaft 22 at an angle such that when the container 12 is rocked to its uppermost feed position, represented by FIG. 2, the lever arm 21 and the lever arm 23 are displaced into a position in which the shoe 28 becomes pressed against the shaft 30 to increase the pressure relationship between the rollers 10 and 11 as previously described. When the container 12 is rotated to its lowermost position, the shoe 28 is withdrawn to release the roller 11 for return to its relaxed position or to release the roller 11 to enable removal for cleaning or replacement.

It will be apparent from the foregoing that I have provided improvements in developing devices of the type described which will enable simplification in construction and operation and which will enable more effective utilization of the device for use in the production of copy by the diffusion transfer techniques.

It will be understood that changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. In a device for the production of copy by diffusion transfer from an exposed negative to a coated positive sheet comprising a tank for holding a developing liquid, a guide means for separating the exposed negative and the positive sheet during advancement into the tank and a pair of squeeze rollers for pressing the exposed negative and coated positive sheets together in advance of delivery from the tank, the improvement which comprises means for maintaining the developing liquid in the tank at a predetermined level, means for mounting the squeeze rollers on the tank beyond the guide means and above the liquid level with at least one of the squeeze rollers being mounted for displacement in the direction towards and away from the other and in which said guide means comprises a guide plate for separating the coated positive sheet from the exposed negative during advancement into the tank and in which the plate extends angularly downwardly into the tank to a level below the liquid level and then turns curvilinearly upwardly toward the squeeze rollers to a level above the liquid level whereby the negative sheet advanced into the tank adjacent thebottom side of the guide plate becomes wet with developing liquid while the coated positive sheet advanced into the tank adjacent the top of the guide plate remains free of the developing liquid and in which the means for maintaining the liquid in the tank comprises a pair of vertically spaced apart apertures separately connected to a source of supply of developing liquid, means mounting the source of supply for rocking movement to raised position above said apertures to cause developing liquid to flow into the tank to a level corresponding to the lower edge of the upper aperture and to a lowered position below the apertures whereby the developing liquid drains from the tank to a level corresponding to the lower edge of the lowermost aperture, and means rwponsive to said rocking movement of the source of supply between raised and lowered positions for displacement of the one squeeze roller in the direction towards and away from the other respectively.

2. A device as claimed in claim 1 in which the means responsive to rocking movement of the source of supply for displacement of the squeeze roller comprises a shaft rotatably mounted on the tank, a first lever arm fixed to the shaft for rotational movement therewith, an operative connection between the first lever arm and the source of developing liquid for rocking movement of the arm responsive to movement of the source between raised and lowered positions, a second lever arm fixed to the shaft for rocking movement therewith, a linking member pivoted at one end onto the second lever arm and engaging the squeeze roller at the other end whereby in response to the raising and lowering of the source of supply of developing liquid the roller is displaced in the direction toward and away from the other squeeze roller in the pair.

3. In a device for the production of copy by dilfusion transfer from an exposed negative to a coated positive sheet, a tank for holding a developing liquid, guide means for separating the exposed negative and the positive sheet during advancement into the tank, means for maintaining developing liquid in the tank at a predetermined level, a pair of squeeze rollers beyond the guide means and above the liquid level through which the exposed negative and coated positive sheet are advanced upon emission from the device, at least one of the squeeze rollers in the pair being mounted for movement in the direction toward and away from the other, and in which the means for maintaining the liquid in the tank comprises a pair of vertically spaced apart apertures separately connected to a source of supply of developing liquid, means mounting the source for movement between raised position above said apertures to cause developing liquid to flow into the tank to a level corresponding to the lower edge of the uppermost aperture and to a lowered position below said apertures whereby the developing liquid drains from the tank to a level corresponding to the lower edge of the lowermost aperture, and means responsive to movement of the source of supply of developing liquid between raised and lowered positions for displacement of the displaceable squeeze roller in the direction toward and away from the other squeeze roller respectively.

4. A device as claimed in claim 3 in which the means responsive to rocking movement of the source of supply for displacement of the squeeze roller comprises a shaft rotatably mounted on the tank, a first lever arm fixed to the shaft for rotational movement therewith, an operative connection between the first lever arm and the source of developing liquid for rocking movement of the arm responsive to movement of the source between raised and lowered positions, a second lever arm fixed to the shaft for rocking movement therewith, a linking member pivoted at one end onto the second lever arm and engaging the squeeze roller at the other end whereby in response to raising and lowering of the source of supply of developing liquid the roller is displaced in the direction toward and away from the other squeeze roller in the pair.

References Cited UNITED STATES PATENTS 2,664,801 1/1954 Eisbein 89 3,095,796 7/1963 Dubois et a1 95-89 3,186,325 6/1965 Belder 9589 3,203,335 8/1965 Wanielista et al. 95-89 FOREIGN PATENTS 1,118,607 11/1961 Germany.

75,070 1/ 1954 Netherlands.

NORTON ANSHER, Primary Examiner. F. L, BRAUN, Assistarvt Examiner. 

1. IN A DEVICE FOR THE PRODUCTION OF COPY BY DIFFUSION TRANSFER FROM AN EXPOSED NEGATIVE TO A COATED POSITIVE SHEET COMPRISING A TANK FOR HOLDING A DEVELOPING LIQUID, A GUIDE MEANS FOR SEPARATING THE EXPOSED NEGATIVE AND THE POSITIVE SHEET DURING ADVANCEMENT INTO THE TANK AND A PAIR OF SQUEEZE ROLLERS FOR PRESSING THE EXPOSED NEGATIVE AND COATED POSITIVE SHEETS TOGETHER IN ADVANCE OF DELIVERY FROM THE TANK, THE IMPROVEMENT WHICH COMPRISES MEANS FOR MAINTAINING THE DEVELOPING LIQUID IN THE TANK AT A PREDETERMINED LEVEL, MEANS FOR MOUNTING THE SQUEEZE ROLLERS ON THE TANK BEYOND THE GUIDE MEANS AND ABOVE THE LIQUID LEVEL WITH AT LEAST ONE OF THE SQUEEZE ROLLERS BEING MOUNTED FOR DISPLACEMENT IN THE DIRECTION TOWARDS AND AWAY FROM THE OTHER AND IN WHICH SAID GUIDE MEANS COMPRISES A GUIDE PLATE FOR SEPARATING THE COATED POSITIVE SHEET FROM THE EXPOSED NEGATIVE DURING ADVANCEMENT INTO THE TANK AND IN WHICH THE PLATE EXTENDS ANGULARLY DOWNWARDLY INTO THE TANK TO A LEVEL BELOW THE LIQUID LEVEL AND THEN TURNS CURVILINERALY UPWARDLY TOWARD THE SQUEEZE ROLLERS TO A LEVEL ABOVE THE LIQUID LEVEL WHEREBY THE NEGATIVE SHEET ADVANCED INTO THE TANK ADJACENT THE BOTTOM SIDE OF THE GUIDE PLATE BECOMES WET WITH DEVELOPING LIQUID WHILE THE COATED POSITIVE SHEET ADVANCED INTO THE TANK ADJACENT THE TOP OF THE GUIDE PLATE REMAINS FREE OF THE DEVELOPING LIQUID AND IN WHICH THE MEANS FOR MAINTAINING THE LIQUID IN THE TANK COMPRISES A PAIR OF VERTICALLY SPACED APART APERTURES SEPARATELY CONNECTED TO A SOURCE OF SUPPLY OF DEVELOPING LIQUID, MEANS MOUNTING THE SOURCE OF SUPPLY FOR ROCKING MOVEMENT TO RAISED POSITION ABOVE SAID APERTURES TO CAUSE DEVELOPING LIQUID TO FLOW INTO THE TANK TO A LEVEL CORRESPONDING TO THE LOWER EDGE OF THE UPPER APERTURE AND TO A LOWERED POSITION BELOW THE APERTURES WHEREBY THE DEVELOPING LIQUID DRAINS FROM THE TANK TO A LEVEL CORRESPONDING TO THE LOWER EDGE OF THE LOWERMOST APERTURE, AND MEANS RESPONSIVE TO SAID ROCKING MOVEMENT OF THE SOURCE OF SUPPLY BETWEEN RAISED AND LOWERED POSITIONS FOR DISPLACEMENT OF THE ONE SQUEEZE ROLLER IN THE DIRECTION TOWARDS AND AWAY FROM THE OTHER RESPECTIVELY. 